To find the area of the shaded region, we have to find the area of the square first.
Then, we find the area of each yellow triangle inside (up and down). The base of each triangle is 10 inches, and the height of each of them is 7 inches.
Add the area of both triangles.
At last, subtract the area of the triangles from the area of the square.
Therefore, the area of the shaded region is 30 in^2.
The strategy is to subtract the area of the yellow triangles (up and down) from the area of the square.